I, a 15M got cheated on by my 16F girlfriend, I wrote this text to send her but, I don't think she deserves to see it. I just need somewhere to vent and get some advice. (Update)

Hello everyone, I recently posted on this sub seeking advice on whether I should send a text being vulnerable and open to my cheating ex girlfriend. The overwhelming majority of people said to not to send the text and to immediately block her. I decided that deep down this was the right answer all along. Last night I decided to text her and I told her the following. “I have forgiven you for what you did but that doesn’t mean I want to be with you. What you did wasn’t nice or respectful and it’s ok because you did and that can’t be changed but that doesn’t mean that I have to tolerate that treatment. Thank you for everything and I wish you well. Happy New Year.” I thought the best way to end the relationship was not to be hateful towards her. She made a mistake that happens, but I don‘t want to be with her anymore and that is my choice and also ok. I know a lot of people were saying to not say anything to her but we compete in the same sport at the same club for up to 2 hours, 10 times a week. I thought this text would help as she would know to leave me alone and my decision was made clear. She responded to the text this morning. She said “i’m so sorry that i did this and i’m happy u forgive me. if this is what u want i’m happy for you and i wish you the best and i hope u find someone who will never do this to you and treats you better. i’ll 100% learn from this, thank you for everything” Her response made this especially hard for me as she seemed so sincere but then I looked back at the night she told me and remembered how sad I felt. I remembered what I wrote and decided it was for the best. The next weeks will be hard and probably lonely but it will pass. Thank you to everyone who left a comment and helped me out. Sending much love.